<template>
    <div>
        <router-link to='/' tag='div'  class="header-abs" v-show='showAbs'>
            <div class="iconfont icon-fanhui header-abs-icon"></div>
        </router-link>
        <div class="header-fixed" v-show='!showAbs' :style="opacityStyle">
            <router-link to='/'>
                <div class="iconfont icon-fanhui header-fixed-icon"></div>
            </router-link>
            景点详情
        </div>
    </div>
</template>
<script>
export default {
  name: 'DetailHeader',
  data () {
    return {
      showAbs: true,
      opacityStyle: {
        opacity: 0
      }
    }
  },
  mounted () { // 页面展示的时候显示
    window.addEventListener('scroll', this.handleScroll)
  },
  unmounted () { // 页面隐藏的时候隐藏
    window.removeEventListener('scroll', this.handleScroll)
  },
  methods: {
    handleScroll () {
      const top = document.documentElement.scrollTop
      if (top > 60) {
        let opacity = top / 140
        opacity = opacity > 1 ? 1 : opacity
        this.opacityStyle = {
          opacity
        }
        this.showAbs = false
      } else {
        this.showAbs = true
      }
    }
  }
}
</script>
<style lang='stylus' scoped>
@import '~styles/varibles.styl'
.header-abs
  position absolute
  left .2rem
  top .2rem
  width .8rem
  height .8rem
  line-height .8rem
  border-radius .4rem
  text-align center
  background rgba(0,0,0,0.8)
  .header-abs-icon
    color #ffffff
    font-size .4rem
.header-fixed
  z-index 2
  position fixed
  top 0
  right 0
  left 0
  height $headerHeight
  line-height $headerHeight
  text-align center
  color #ffffff
  background $bgColor
  font-size .32rem
  .header-fixed-icon
    position absolute
    width .64rem
    text-align center
    font-size .24rem
    top 0
    left 0
    color #ffffff
</style>
